The present invention relates to a so-called loop drive wherein a carriage is provided for guiding a ribbon tape or strip and is itself moved through an arrangement of ropes or cables. The cable has one end anchored to a stationary point and is deflected by means of pulleys or the like and is run to the carriage to be driven and back to a winch. On turning the winch for unwinding or taking up the cable, the carriage is moved in one direction or the other.
It was found to be a disadvantage that in such a drive system the cable moves laterally upon winding and unwinding from the winch while a particular take-up angle has to be maintain between the winch and the cable. Another disadvantage is to be seen that in case of a fast movement of the carriage, particularly towards the winch, or if for some reason the ribbon suddenly breaks, the carriage may be run against a baffle or bumper without prior breaking, which may lead to damage in the carriage or other equipment.
In order to avoid the aforementioned drawbacks, it is known to guide the carriage by means of a main or tension cable and to provide separately a capturing or hauling cable. The principle and tension cable will run over pulleys to the side of the carriage facing away from the ribbon, tape or strip while the capturing or hauling cable is run through rollers to the side or end of the carriage manipulating the ribbon, there being still another deflection pulley for running this capturing cable also to the winch. This arrangement has the advantage that owing to the combination of a tension cable and of a hauling or capturing cable, the carriage can be guided very accurately that means in any direction and it can actually be driven to and stopped at a particular point. However, it is a disadvantage that even here a winch is needed which has to take up the principle or tension cable as well as the capturing cable.